As Martin suggested dry hopping can be one of the biggest factors in O2 ingress. One thing you can try is adding your hops to a keg, purging the keg with co2 then racking the beer onto the hops (via closed transfer if possible). You can also add the hops near the end of active fermentation so that the yeast scavenge the o2.

I always have experience yeast activity after dry hopping. This will take care of any free oxygen. There was a study at MBAA that talk about “dry hop creep” that some hops could have enzyme to break dextrens and allow for refermentation.

Last thing you can have stailing of your beer even with out oxygen due to too much FAN and fatty acids.

I am like a walking knowledge. I just returned from Malt U

Hop Creep is certainly real but I havent found it to be enough to avoid oxidation pitfalls.

As Martin suggested dry hopping can be one of the biggest factors in O2 ingress. One thing you can try is adding your hops to a keg, purging the keg with co2 then racking the beer onto the hops (via closed transfer if possible). You can also add the hops near the end of active fermentation so that the yeast scavenge the o2.

I always have experience yeast activity after dry hopping. This will take care of any free oxygen. There was a study at MBAA that talk about “dry hop creep” that some hops could have enzyme to break dextrens and allow for refermentation.

Last thing you can have stailing of your beer even with out oxygen due to too much FAN and fatty acids.

I am like a walking knowledge. I just returned from Malt U

Hop Creep is certainly real but I havent found it to be enough to avoid oxidation pitfalls.

I actually tried to make hop creep happen to study the effects. 2 tries so far no hop creep. 3rd try coming up.

Trick is, if you seal it up and build a little vacuum during cooling, you're just delaying the inevitable. When you pull the stopper, the air will rush in. Less contact time though, maybe, if you do a quick closed-ish (it's already not closed) transfer. If equipment permits, putting a couple of psi of CO2 on the fermentor before crashing will solve this. It takes surprisingly little.

If you wait until the beer & vessel have returned to room temp then there is no vacuum, hence no inrushing of air when the stopper is pulled. I generally remove the FV from the fridge the day before I plan on bottling. I also do my best to purge the headspace with CO2 any time I have the lid off, i.e. sampling, dry hopping etc., I realize there will always be some infiltration of air, but every little bit of purging helps some. For those using conicals with sediment jars, I recommend purging the jar with CO2 after harvesting and before re-attaching to the FV, I know that seems obvious, but it took me a while to think of that one, but I was one of the short bus kids.

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I spent most of my money on beer, tools and guns, the rest I foolishly squandered on stupid stuff!

Wow. Thanks for all the input. Major brew geeking out going on here. Love it.

I think the biggest problem for my brew is oxygen introduction in secondary transfer as well as in the cold crash.

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Is there a reason you're using a secondary?

Educate me please if I’m wrong. Not using a conical fermenter. Maybe I should invest. I’m transferring to secondary for dry hop then cold crash.

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Well, it sounds like you have a reason. I seldom use a secondary but dry hopping is an exception for me. I cold crash the primary, xfer to secondary, dry hop and crash again.

I seldom dry hop, but when I do it's in the primary with some fermenting left to do. Using the stainless mesh canisters for the hops I can even keep the yeast clean enough for harvesting and repitching. And I'm not using a conical either. If it's at all possible with whatever fermenter one is using, then I don't see a need for transfer.

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Rob Stein Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

Wow. Thanks for all the input. Major brew geeking out going on here. Love it.

I think the biggest problem for my brew is oxygen introduction in secondary transfer as well as in the cold crash.

Sent from my iPhone using Tapatalk

Is there a reason you're using a secondary?

Educate me please if I’m wrong. Not using a conical fermenter. Maybe I should invest. I’m transferring to secondary for dry hop then cold crash.

Sent from my iPhone using Tapatalk

Well, it sounds like you have a reason. I seldom use a secondary but dry hopping is an exception for me. I cold crash the primary, xfer to secondary, dry hop and crash again.

I seldom dry hop, but when I do it's in the primary with some fermenting left to do. Using the stainless mesh canisters for the hops I can even keep the yeast clean enough for harvesting and repitching. And I'm not using a conical either. If it's at all possible with whatever fermenter one is using, then I don't see a need for transfer.

I don't care for the effects of doing dry hops on yeast. To me, that's worse than any possible oxidation.

As Martin suggested dry hopping can be one of the biggest factors in O2 ingress. One thing you can try is adding your hops to a keg, purging the keg with co2 then racking the beer onto the hops (via closed transfer if possible). You can also add the hops near the end of active fermentation so that the yeast scavenge the o2.

I always have experience yeast activity after dry hopping. This will take care of any free oxygen. There was a study at MBAA that talk about “dry hop creep” that some hops could have enzyme to break dextrens and allow for refermentation.

Last thing you can have stailing of your beer even with out oxygen due to too much FAN and fatty acids.

I am like a walking knowledge. I just returned from Malt U

Hop Creep is certainly real but I havent found it to be enough to avoid oxidation pitfalls.

I actually tried to make hop creep happen to study the effects. 2 tries so far no hop creep. 3rd try coming up.

Keith, I have experienced refermentation after dry hoping after reaching terminal gravity. My only explanation is that it is availability of oxygen and enzyme activity from dry hops. Granted I was using 3.5lb/BBL.

Last thing you can have stailing of your beer even with out oxygen due to too much FAN and fatty acids.

Yes. Although the LODO people use the term oxidation to refer to all staling, there other mechanisms.

The issue is not that simple.

It is barley variety dependent. If barley variety would have less FAN then it would have more Bata Glucain and via versa. Yeast needs some FAN but if too much is left over, that will make stailing.

You can find FAN levels from Malt Analyses.

The particular staling mechanism involved is called Strecker (sp?) degradation, in case that might direct you to further sources.

While FAN should be available on the COA, it may be of little help if one does not have an idea of how much FAN yeast can consume in one's process.

Prudent practice is to use malt with low total nitrogen (trusting that the maltster has appropriately balanced FAN, beta glucan, and other parameters) and minimize all other risk factors for staling reactions: mash in above 60°C, and minimize thermal loading, oxygen, etc. through the whole process, and pitch an appropriate (not excessive) amount of yeast with good vitality and viability to maximize growth.

Denny - I have definitely experienced hop creep .... very much in unfortunate instances. Think of a $50,000 recall and you will understand how unfortunate. At YH we would force age, force ferment, and inventory EVERYTHING. I've seen it happen on more than one occasion. FYI I also believe in biotransformation... that's also a very real phenomenon. Just sayin'.

Besides podcasts, there are some old fashioned papers from 1893 that cover the topic pretty thoroughly; in fact I don't think I've seen anything really significant added to the subject since! Then some more papers around 1939 (publication delayed by war) rediscovering and reexamining and confirming those. Then the whole thing rediscovered again now....

Back in the 19th century, dry hop creep was depended upon and taken for granted. It was the primary reason for dry hopping. It ensured full attenuation and the elimination of sugars unfermentable by culture yeast that might feed spoilers.

Flavor and aroma weren't considerations for dry hopping then; the beers were sufficiently aged that hop character would be nearly absent by the time of release. The only other function was providing tannin to complex with protein and help clarification. Like the modern use of gallotannin in the aging tank.

One thing the original studies note that I haven't seen (might have missed) addressed in the recent work is that seeded hops may contain more amylase than seedless (IIRC this assertion of the 1893 study was questioned by the 1939 work.) I wonder if some hops today might be deseeded prior to pelletizing, leading to inconsistent results in producing dry hop creep. Maybe there are other differences in modern varieties as well.

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Rob Stein Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.